- ID:
- ivo://CDS.VizieR/J/A+A/571/A63
- Title:
- New catalogue of one-apparition comets
- Short Name:
- J/A+A/571/A63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The orbits of one-apparition comets discovered in the early part of the last century have formerly been determined with very different numerical methods and assumptions on the model of the solar system, including the number of planets taken into account. Moreover, observations of the comet-minus-star-type sometimes led to determination of the comet position that are less precise than what we can derive today by using a more modern star catalogue. We aim to provide a new catalogue of cometary orbits that are derived using a completely homogeneous data treatment, accurate numerical integration, and a modern model of the solar system. We collected the complete sets of observations for investigated comets from the original publications. Then we recalculated the cometary positions for the comet-minus-star-type of observations using the Positions and Proper Motions Star Catalogue, and applied a uniform method for the data selection and weighting. As a final result, new osculating orbits were determined. Secondly, dynamical calculations were performed to the distance of 250AU from the Sun to derive original and future barycentric orbits for evolution backward and forward in time. These numerical calculations for a given object start from a swarm of virtual comets constructed using our osculating (nominal) orbit. In this way, we obtained the orbital element uncertainties of original and future barycentric orbits.
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- ID:
- ivo://CDS.VizieR/J/A+A/634/L6
- Title:
- NIR spectrum of interstellar object 2I/Borisov
- Short Name:
- J/A+A/634/L6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Interstellar objects (ISOs) passing through our Solar System offer a rare opportunity to probe the physical and chemical processes involved in solid body and planet formation in extrasolar systems. The main objective of our study is to search for diagnostic absorption features of water ice in the near-infrared (NIR) spectrum of the second interstellar object 2I/2019 Q4 (Borisov) and compare its ice features to those of the Solar System icy objects. We observed 2I in the NIR on three separate occasions. The first observation was made on 2019 September 19 UT using the SpeX spectrograph at the 3m IRTF and again on September 24 UT with the GNIRS spectrograph at the 8m GEMINI telescope; the last observation was made on October 09 UT with IRTF. The spectra obtained from all three nights appear featureless. No absorption features associated with water ice are detected. Spectral modeling suggests that water grains, if present, comprise no more than 10% of the coma cross section. The comet consistently exhibits a red D-type like spectrum with a spectral slope of about 6% per 1000~\AA, which is similar to that of 1I/'Oumuamua and is comparable to Solar System comets.
- ID:
- ivo://CDS.VizieR/J/A+AS/146/73
- Title:
- Nuclear magnitudes of Jupiter family comets
- Short Name:
- J/A+AS/146/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalog of a sample of 105 Jupiter family (JF) comets (defined as those with Tisserand constants T>2 and orbital periods P<20yr) is presented with our ``best estimates'' of their absolute nuclear magnitudes H_N_=V(1,0,0). The catalog includes all the nuclear magnitudes reported after 1950 until August 1998 that appear in the International Comet Quarterly Archive of Cometary Photometric Data, the Minor Planet Center (MPC) data base, IAU Circulars, International Comet Quarterly, and a few papers devoted to some particular comets, together with our own observations. Photometric data previous to 1990 have mainly been taken from the Comet Light Curve Catalogue (CLICC) compiled by Kamel (1991, The comet light curve catalogue/atlas. I. The compiled observations. Uppsala Univ. Reprocentralen HSC). Most absolute nuclear magnitudes are found in the range 15-18, with no magnitudes fainter than H_N_~19.5.
- ID:
- ivo://CDS.VizieR/J/AJ/156/223
- Title:
- Observations of the main-belt comets 238P & 288P
- Short Name:
- J/AJ/156/223
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report observations of the reactivations of the main-belt comets (MBCs) 238P/Read and 288P/(300163) 2006 VW_139_ that also track the evolution of each object's activity over several months in 2016 and 2017. We additionally identify and analyze archival SDSS data showing 288P to have been active in 2000, meaning that both 238P and 288P have now each been confirmed to be active near perihelion on three separate occasions. From data obtained of 288P from 2012-2015 when it appeared inactive, we find best-fit R-band H, G phase function parameters of H_R_=16.80+/-0.12 mag and G_R_=0.18+/-0.11, corresponding to effective component radii of r_c_=0.80+/-0.04 km, assuming a binary system with equally sized components. Fitting linear functions to ejected dust masses inferred for 238P and 288P soon after their observed reactivations in 2016, we find an initial average net dust production rate of M_d_=0.7+/-0.3 kg/s and a best-fit start date of 2016 March 11 (when the object was at a true anomaly of {nu}=-63{deg}) for 238P, and an initial average net dust production rate of M_d_=5.6+/-0.7 kg/s and a best-fit start date of 2016 August 5 (when the object was at {nu}=-27{deg}) for 288P. Applying similar analyses to archival data, we find similar start points for previous active episodes for both objects, suggesting that minimal mantle growth or ice recession occurred between the active episodes in question. Some changes in dust production rates between active episodes are detected, however. More detailed dust modeling is suggested to further clarify the process of activity evolution in MBCs.
- ID:
- ivo://CDS.VizieR/J/ApJ/793/50
- Title:
- Observed light curve of (3200) Phaethon
- Short Name:
- J/ApJ/793/50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (3200) Phaethon exhibits both comet- and asteroid-like properties, suggesting it could be a rare transitional object such as a dormant comet or previously volatile-rich asteroid. This justifies detailed study of (3200) Phaethon's physical properties as a better understanding of asteroid-comet transition objects can provide insight into minor body evolution. We therefore acquired time series photometry of (3200) Phaethon over 15 nights from 1994 to 2013, primarily using the Tektronix 2048x2048 pixel CCD on the University of Hawaii 2.2 m telescope. We utilized light curve inversion to (1) refine (3200) Phaethon's rotational period to P=3.6032+/-0.0008 hr; (2) estimate a rotational pole orientation of {lambda}=+85{deg}+/-13{deg} and {beta}=-20{deg}+/-10{deg}; and (3) derive a shape model. We also used our extensive light curve data set to estimate the slope parameter of (3200) Phaethon's phase curve as G~0.06, consistent with C-type asteroids. We discuss how this highly oblique pole orientation with a negative ecliptic latitude supports previous evidence for (3200) Phaethon's origin in the inner main asteroid belt as well as the potential for deeply buried volatiles fueling impulsive yet rare cometary outbursts.
- ID:
- ivo://CDS.VizieR/J/ApJ/889/L30
- Title:
- Opt. spectra of the interstellar object 2I/Borisov
- Short Name:
- J/ApJ/889/L30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 2I/Borisov is the first-ever observed interstellar comet (and the second detected interstellar object (ISO)). It was discovered on 2019 August 30 and has a heliocentric orbital eccentricity of ~3.35, corresponding to a hyperbolic orbit that is unbound to the Sun. Given that it is an ISO, it is of interest to compare its properties-such as composition and activity-with the comets in our solar system. This study reports low-resolution optical spectra of 2I/Borisov. The spectra were obtained by the MDM Observatory Hiltner 2.4m telescope/Ohio State Multi-Object Spectrograph (on 2019 October 31.5 and November 4.5, UT). The wavelength coverage spanned from 3700 to 9200{AA}. The dust continuum reflectance spectra of 2I/Borisov show that the spectral slope is steeper in the blue end of the spectrum (compared to the red). The spectra of 2I/Borisov clearly show CN emission at 3880{AA}, as well as C2 emission at both 4750 and 5150{AA}. Using a Haser model to covert the observed fluxes into estimates for the molecular production rates, we find Q(CN)=2.4+/-0.2x10^24^s^-1^, and Q(C_2_)=(5.5+/-0.4)x10^23^s^-1^ at the heliocentric distance of 2.145au. Our Q(CN) estimate is consistent with contemporaneous observations, and the Q(C_2_) estimate is generally below the upper limits of previous studies. We derived the ratio Q(C_2_)/Q(CN)=0.2+/-0.1, which indicates that 2I/Borisov is depleted in carbon-chain species, but is not empty. This feature is not rare for the comets in our solar system, especially in the class of Jupiter-family comets.
- ID:
- ivo://CDS.VizieR/J/ApJ/889/L38
- Title:
- Opt. spectroscopic investigations of 2I/Borisov
- Short Name:
- J/ApJ/889/L38
- Date:
- 17 Jan 2022 00:14:14
- Publisher:
- CDS
- Description:
- The composition of comets in the solar system comes in multiple groups thought to encode information about their formation in different regions of the outer protosolar disk. The recent discovery of the second interstellar object, 2I/Borisov, allows for spectroscopic investigations into its gas content and a preliminary classification of it within the solar system comet taxonomies to test the applicability of planetesimal formation models to other stellar systems. We present spectroscopic and imaging observations from 2019 September 20 through October 26 from the Bok, MMT telescope (formerly the Multiple Mirror Telescope, Mount Hopkins, Arizona), and Large Binocular Telescopes. We identify CN in the comet's spectrum and set precise upper limits on the abundance of C_2_ on all dates in October. We use a Haser model to convert our integrated fluxes to production rates and find Q(CN)=(1.1-1.9)*10^24^mols/s increasing over 2019 October 1 to 26, consistent with contemporaneous observations. We set our lowest upper limit on a C_2_ production rate, Q(C_2_)<1.6*10^23^mols/s on 2019 October 10. The measured upper limit ratio for that date Q(C_2_)/Q(CN)<0.1 indicates that 2I/Borisov is strongly in the (carbon-chain) "depleted" taxonomic group if there is any C_2_ production at all. Most "depleted" comets are Jupiter-family comets (JFCs), perhaps indicating a similarity in formation conditions between the most depleted of the JFCs and 2I/Borisov. More work is needed to understand the applicability of our knowledge of solar system comet taxonomies onto interstellar objects and we discuss future work that could help to clarify the usefulness of the approach.
- ID:
- ivo://CDS.VizieR/J/A+A/548/A12
- Title:
- 67P/Churyumov-Gerasimenko R-band light curve
- Short Name:
- J/A+A/548/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Comet 67P/Churyumov-Gerasimenko is the target of the European Space Agency Rosetta spacecraft rendez-vous mission. Detailed physical characteristation of the comet before arrival is important for mission planning as well as providing a test bed for ground-based observing and data-analysis methods. To conduct a long-term observational programme to characterize the physical properties of the nucleus of the comet, via ground-based optical photometry, and to combine our new data with all available nucleus data from the literature. We applied aperture photometry techniques on our imaging data and combined the extracted rotational lightcurves with data from the literature. Optical lightcurve inversion techniques were applied to constrain the spin state of the nucleus and its broad shape. We performed a detailed surface thermal analysis with the shape model and optical photometry by incorporating both into the new Advanced Thermophysical Model (ATPM), along with all available Spitzer 8-24um thermal-IR flux measurements from the literature. A convex triangular-facet shape model was determined with axial ratios b/a=1.239 and c/a=0.819. These values can vary by as much as 7% in each axis and still result in a statistically significant fit to the observational data. Our best spin state solution has P_sid_=12.76137+/-0.00006 hrs, and a rotational pole orientated at Ecliptic coordinates lambda=78{deg}(+/-10{deg}), beta=+58{deg}(+/-10{deg}). The nucleus phase darkening behaviour was measured and best characterized using the IAU HG system. Best fit parameters are: G=0.11+/-0.12 and H_R(1,1,0)_=15.31+/-0.07. Our shape model combined with the ATPM can satisfactorily reconcile all optical and thermal-IR data, with the fit to the Spitzer 24um data taken in February 2004 being exceptionally good. We derive a range of mutually-consistent physical parameters for each thermal-IR data set, including effective radius, geometric albedo, surface thermal inertia and roughness fraction. The overall nucleus dimensions are well constrained and strongly imply a broad nucleus shape more akin to comet 9P/Tempel 1, rather than the highly elongated or `bilobed' nuclei seen for comets 103P/Hartley 2 or 8P/Tuttle. The derived low thermal inertia of <15J/m^2^/K/s^1/2^ is comparable with that measured for other comets scaled to similar heliocentric distances, and implies a surface regolith finer than lunar surface material.
- ID:
- ivo://CDS.VizieR/J/A+A/527/A113
- Title:
- 67P/Churyumov-Gerasimenko R-band light curve
- Short Name:
- J/A+A/527/A113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Jupiter family comet (JFC) 67P/Churyumov-Gerasimenko is the target of the ESA's ROSETTA mission. Observational campaigns and theoretical investigations were performed to characterise 67P/C-G in terms of nucleus properties (e.g. size, surface colors, rotational period), gas and dust production, and plasma environment in preparation for the rendezvous with the spacecraft; however, there are still open questions which need to be addressed. Our observations of 67P/C-G are important not only for good planning of the rendezvous of the ROSETTA spacecraft with 67P/C-G, but also provide valuable information on the basic physical properties of the nuclei of JFCs at large heliocentric distances. Moreover, this information will also help to identify to what extent 67P/C-G is a typical JFC.
- ID:
- ivo://CDS.VizieR/J/A+A/374/712
- Title:
- Photometric observations of comets
- Short Name:
- J/A+A/374/712
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD VRc photometry of 3 distant active comets visible in July, 2000. Time-series data cover 16 hours. Data were obtained with the 1.23m telescope of the German-Spanish Astronomical Centre, Calar Alto.
